PCI: layerscape: Allow to compile as module

The layerscape pcie host controller could also be compiled as module.
Add the necessary infrastructure to allow building as module instead of
only as builtin driver.

Since the driver doesn't expose an irqchip controller, it is also safe to
be removed during runtime.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
[mani: added a note about driver removability]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Acked-by: Roy Zang <Roy.Zang@nxp.com>
Link: https://patch.msgid.link/20260112-v6-19-topic-layerscape-pcie-v1-1-1cd863fce50e@pengutronix.de

Author: saschahauer

drivers/pci/controller/dwc/Kconfig

@@ -121,7 +121,7 @@ config PCI_IMX6_EP
 	  DesignWare core functions to implement the driver.
 
 config PCI_LAYERSCAPE
-	bool "Freescale Layerscape PCIe controller (host mode)"
+	tristate "Freescale Layerscape PCIe controller (host mode)"
 	depends on OF && (ARM || ARCH_LAYERSCAPE || COMPILE_TEST)
 	depends on PCI_MSI
 	select PCIE_DW_HOST

drivers/pci/controller/dwc/pci-layerscape.c

@@ -13,6 +13,7 @@
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/iopoll.h>
+#include <linux/module.h>
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
 #include <linux/of_address.h>
@@ -403,13 +404,26 @@ static const struct dev_pm_ops ls_pcie_pm_ops = {
 	NOIRQ_SYSTEM_SLEEP_PM_OPS(ls_pcie_suspend_noirq, ls_pcie_resume_noirq)
 };
 
+static void ls_pcie_remove(struct platform_device *pdev)
+{
+	struct ls_pcie *pcie = platform_get_drvdata(pdev);
+
+	dw_pcie_host_deinit(&pcie->pci->pp);
+}
+
 static struct platform_driver ls_pcie_driver = {
 	.probe = ls_pcie_probe,
+	.remove = ls_pcie_remove,
 	.driver = {
 		.name = "layerscape-pcie",
 		.of_match_table = ls_pcie_of_match,
 		.suppress_bind_attrs = true,
 		.pm = &ls_pcie_pm_ops,
 	},
 };
-builtin_platform_driver(ls_pcie_driver);
+module_platform_driver(ls_pcie_driver);
+
+MODULE_AUTHOR("Minghuan Lian <Minghuan.Lian@freescale.com>");
+MODULE_DESCRIPTION("Layerscape PCIe host controller driver");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, ls_pcie_of_match);